Those with 20/20 vision can see a letter of the same size on the eye chart that most people without refractive errors can see. While this test of visual acuity may be perfect, other facets of vision are equally important. For instance, vision may be blurred at nearer distances, which is important to note because most reading is done at a distance closer than 20 feet. A comprehensive eye exam will also note how well focus changes from far to near and back to far again. In addition, the eyes must work in tandem as they follow objects be able to converge rapidly or point to a moving object simultaneously. Comfortable and efficient vision involves more than visual acuity. Routine eye exams can detect vision problems, eye disease and general health problems before you are aware a problem exists. Visual field tests check for gaps in side (peripheral) vision.